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Extraction of Caffeine

DiscussionIn this experiment, Caffeine was extracted from a commercial tea bag through solid-liquid extraction, and then further purified through sublimation. To begin the extraction, the commercial tea bag containing ~55mg of caffeine was placed in a mixture containing 2.2g of anhydrous sodium carbonate along with 20 ml of D.I. water. The sodium carbonate was placed into the solution to keep the caffeine from becoming slightly acidic(protonated), which would prevent the caffeine from being able to be separated once the organic solvent (dichloromethane) was added to the solution, as a charged species dissolves in the aqueous layer while a neutral species goes to the organic layer. The caffeine also dissolves in the organic layer due to similar intermolecular forces with dichloromethane. Once the organic solvent was added, the solution was centrifuged to get rid of the emulsions and the bottom organic layer containing the caffeine was extracted. The reason the organic layer was at the bottom is because dichloromethane is denser than water, causing the aqueous layer to float towards the top. This extraction method was done a total of four times to ensure that most of the caffeine was able to be extracted from the aqueous layer. To make sure that no water was present in the extracted solution, the solution was ran through a glass funnel that contained 2.5g of the drying agent anhydrous sodium sulfate. The sodium sulfate crystals bind to any water molecules present in the solution and form crystalline hydrates in the funnel while the dry caffeine is extracted into a flask. The dry caffeine was then evaporated on a hot plate and the crude product was recovered with a percent recovery of 193% (106mg). As the results show, the crude caffeine product was much higher than the amount of caffeine that was contained in the commercial tea bag (55mg). This means that the product that was recovered still contained impurities and needed to be further purified. This...

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Extraction is a technique for isolating and purifying organic substances. In this technique, a solution is combined thoroughly with a second solvent that is immiscible with the first solvent. The solute is extracted from one solvent into the other because it is more soluble in the second solvent than in the first.
In this experiment, there were two types of extraction used and these were the Liquid-liquid extraction and Solid-liquid extraction. Liquid-liquid extraction involves a liquid solvent to remove a liquid component from liquid while Solid-liquid extraction allows soluble components to be removed from solids using a solvent. These two types of extraction were used to extract caffeine from tea leaves (Thea sinensis). Caffeine belongs to the group of compounds known as Alkaloids. Alkaloids are a diverse group of compounds that are found in plants and contain basic nitrogen atoms.
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...Extraction of Caffeine from Tea leaves
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Group 4 2MB
Date Submitted: December 13, 2012
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ABSTRACT:
The purpose of this experiment is to extract the amount of caffeine present in tea bags. In this experiment, isolation, characterization and purification of caffeine from tea bags was done through the use of Solvent Extraction and Partitioning method. First, the tea bags were weighed and boiled for five minutes. They were allowed to cool and then they were mixed with dichloromethane. The experimenters performed a technique called single extraction. After the two distinct layers were clearly visible in the separatory funnel, the organic layer or the DCM containing the extracted caffeine in the water was extracted. The process was repeated three times and the collected organic layer (DCM layer) was placed in an Erlenmeyer flask. The combined organic layer was transferred back to the separatory funnel and was washed with sodium hydroxide. After washing, the organic layer was again extracted from the funnel and placed in a beaker containing anhydrous sulphate. The solution was allowed to evaporate to produce crystals of...

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Theory:
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Introduction
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...Abstract: Caffeine, (C8 H10 N4 O2) a white, crystalline alkaloid known as a nervous system stimulant found commonly in tea leaves and coffee, can be extracted using the method of sublimation with the use of Methylene Chloride (CH2Cl2) and Sodium Hydroxide; both can repeatedly rinse the green (unroasted) coffee beans from the caffeine.
Keywords: Caffeine, Methylene Chloride, Sodium Hydroxide, Anhydrous Sodium Sulfate
I. Introduction
Caffeine is an alkaloid of the methylxanthine family. Its chemical formula is C8H10N4O2 and its systematic name is 1,3,7-trimethylxanthine or 3,7-dihydro-1,3,7-trimethyl-1H-purine-2,6-dione (See Fig. 1).
In terms of physical properties, pure caffeine occurs as odorless, white, fleecy masses, glistening needles or powder.
Practically, caffeine is a central nervous system (CNS) stimulant, having the effect of temporarily warding off drowsiness and restoring alertness. Beverages containing caffeine, such as coffee, chocolate, soft drinks, and energy drinks, enjoy great popularity. Caffeine is the world's most widely consumed psychoactive substance, but, unlike many other psychoactive substances, it is legal and unregulated in nearly all jurisdictions. [1]
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...Extraction of Caffeine from Tea Leaves
Introduction
Caffeine is soluble in boiling water and as a result it is easily extracted from tea bags by steeping in hot water. This process leaves behind the water insoluble portions of the tea bag. However, water extracts more than just caffeine, so a final separation is done with an organic solvent that will dissolve primarily caffeine. The organic solvent used in this experiment is Dichloromethane (CH₂Cl₂). Dichloromethane is less polar than water and this difference in polarity allows the separation. Extraction of the tea with the Dichloromethane, followed by evaporation of the organic solvent leaves crude caffeine, which on sublimation yields a relatively pure product. Sublimation is the transition of a substance from the solid phase directly to the gas phase without undergoing intermediate liquifications. This process is preferred over recrystallization because it is better at removing impurities.
Experimental
For this extraction experiment two bags of tea were used, which is approximately 4 grams of tea. Water was heated in a small beaker until it began to boil. It was then removed from heat and 2 grams of Na2CO3 was added and dissolved. Finally the loose tea was added to the water and allowed to steep for 5 minutes. After 5 minutes the mixture was put through a suction filtration. A suction funnel...

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Anza Thomas
10/24/2013
CHE 261 (KC)
Dr . McAtee
Lab : Extraction of Caffiene
Purpose: the purpose of this experiment is to extract caffeine from tea using solvent extraction techinques.
Reference: Williamson, K.; Minard, R.; Masters, K. Macroscale and Microscale Organic Experiments, 2007, p. 137 to 171.
Procedure:
In a 50 mL beaker place 15 mL of water, 2.0059 g of sodium carbonate, and a wooden boiling stick. Bring the water to a boil on the ceramic heating plate. Remove the beaker from the hot plate and remove the boiling stick. Immerse a tea bag in the beaker right after taking it off the hot plate for 4 to 5 minutes. After the tea bag cools enough to handle, squeeze out water as much as possible, being careful not to break tea bag. This can be done easily on a Hirsch funnel. Again bring the water to boil and add a brand new tea bag to the very hot solution for another 4 to 5 minutes. Squeeze out water as much as possible. This time rinse the tea bag with a few mL of very hot water. The more aqueous tea is squeezed out, the more amount of caffeine can be extracted at the end of the experiment. The total volume of aqueous extract was about 10 to 12 mL. Pour the extraction into a 15-mL centrifuge tube. Fill the centrifuge tube about half and use another tube if needed. Use ice bath to bring the temperature of centrifuge tube to room temperature. Add 2 mL of dichloromethane to the...

...Extraction of caffeine from Lipton tea leaves
Maria Gianna Beatrice L. Cancio*, Joe Mari Isabella B. Caringal, Rowena A. Chiang, Patricia Deanne del Valle
Department of Biological Sciences, College of Science, University of Santo Tomas, España, Manila, Philippines
Abstract
Caffeine was extracted from Lipton tea leaves by multiple extraction techniques namely solid to liquid extraction and liquid to liquid extraction; the purification by sublimation and melting point determination. Three teabags with weight 6.2674g were boiled with water and then extracted with 60 mL DCM; extract was dehydrated with anhydride Na2SO4 then was collected by decanting to an evaporating dish where it was evaporated to dryness. Crude caffeine with a weight of 0.0446g gave out a 0.7116% yield; after sublimation, the sublimate weigh 0 .0009g with a percentage yield of 0.0144%. Melting point determination was the last step where the sublimate was compared to a standard caffeine, where both gave out the temperature range of 228 ̊C – 230 ̊C.
Introduction
Caffeine is a bitter substance found in coffee, tea, soft drinks, chocolate, kola nuts and certain medicines. It has many effects on the body’s metabolism, including stimulating the central nervous system. This can make one more alert and give a boost of energy. [1]
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